Improvement in steam-generating furnaces



UNITED STATES PATENT OFFICE.

GEORGE W. CUMMINGS, OF CLEVELAND, OHIO.

IMPROVEMENT IN STEAM-GENERATING FURNACES` Specification forming part ofLetters Patent No. 156,208, dated October 27, 1874 application led i vSeptember 16, 1874.

' ous products in the fire-boxes or furnaces connected withsteam-boilers.

The nature of my invention consists in supplying the incandescent coalsand the gases arising therefrom with oxygen from air and steamintroduced into the lire-box above the furnace-door, and pure airintroduced into the lower part of the dame-bed, back of the bridgewall,and vat one ,or more points between said bridge-wall, and alongthedame-bed between the furnace and the rear end of the boiler, in suchmanner that the large quantity of air introduced and necessarytocomplete combustion shall not operate as a cooling` medium, but shallrather augment the heat, andthereby increase the evaporation going on inthe boiler with the same-or a lesser quantity of fuel and thesuppression of smoke.

To enable others skilled in the art to make and use my invention, I willproceed to describe its construction and operation.

rIhe boiler being constructed in any of the known forms, I introduce acurrent of air to the fuel and flames in the iirebox or furnace `iiue,and said pipe or flue extends laterally acrossthe name-bed and throughboth side walls of the easement, so that, the ends being open, the airfrom the outside of said re-box or easement may have free access to thegases as they pass the bridge-wall on their Way to the iiues of theboiler and the chimney. At one or more points between thefirst-described perforated tube or flue and the rear end of thel boilerI introduce one or more perforated pipes or iiues, extending laterallyacross the iiamebed and through the side walls of the casement, open ateach end to admit the air freely from. without, as in the case of theiirst perforated pipe or flue behind or near the bridgewall. The objectof this arrangement of the tubes, or pipes, or iiues is, thatthe :firstpipe or ue over the furnace-doors or along or within the sides of theeasement or fire-box may, by admitting air to the gases arising from thecombustion of the fuel within said re-box or furnace, thoroughly mixsaid gases, and by supplying said gases at the same time with oxygenfrom the air so introduced initiate the combustion 4of said gases, andas the products of said combustion pass over the bridge-wall in ahighly-heated state a further supply of oxygen is added, and as theflame progresses toward the rear of 'the boiler it receives stillfurther supplies of oxygen to support the com-V bustion in'like mannerthrough the perforated pipes or iues communicating with the atmospherewithout said easement, and thus the combustion is continued untilcompleted.

I perforate the flues or pipes IJ on top and one side for the followingreason, viz., that when the draft from the chimney, which is always moreor less variable, shall. cause the4 currents of air, gas, or vapors fromthe iirebox to pass over the top of said perforated pipes or flues sorapidly as to overcome the atmospheric pressure from without theeasement or fire-box, thereby in effect corking up said top apertures,the side apertures will supply the requisite quantity of air, for thepurpose heretofore stated.

Reference being had to the accompanying drawings, it will be seen thatFigure 1 is a plan view of my invention applied to an ordi nary fire-boxor furnace under a steam-boiler,

the boiler A being removed, in order that an unobstructed View may behad. C represents the grate-bars; E, perforated pipe or chamber over thefire-doors; f, perforated steam-pipe;

G and G,'perforated pipes or chambers in the sides of the fire-box oreasement; I, pipe or 'flue behind the bridge-wall, perforated on top beseveral, at or near the rear end of the casement, and beneath theboiler.

Fig. 2 is a longitudinal Vertical section of the lire-box or furnace andboiler with my apparatus attached, A being the boiler; B, firebox; C,grate-bars; D, ash-pit; E, perforated pipe or chamber over fire-doors; GG', similar perforated pipes or chambers along the sides of theeasement; f, perforated steam-pipe Within the chamber E and the sidechambers G G H, bridge-wall; I, perforated pipe or flue behindbridge-wall J perforated pipe or flue in rear of easement, and atconvenient distances between the bridge-wall and the rear end of theboiler.

I prefer to make the perforations in the air pipes or flues about halfan inch in diameter, and to place them about one and one-half inch apartfrom center to center.

The steam -pipe j' passes from the boiler through the iiue or chamber E,and may also be made to extend down the side tlues or chambers G and G.That part of it inclosed in the .iues or chambers E and G and G isperforated along the inner side, and both ends of the ue or chamber Ebeing open, the steam escaping through the perforations in the steampipef into the said-air iue or flues, and thence through their perforar-ionsintovthe fire-box, draws in a current of air, which passes into theflreboX with the steam.

' In lieu of the perforated pipes or flues I J, and as the equivalentthereof, a similarly perforated horizontal plate may` be ,introducedinto the ame bed or chamber back of the bridge-wall, and extending fromsaid bridgewall baclrto the rear end of the boiler, and from side toside of the easement, forming a perforated door under the flame-bed anda little below the bridge-wall, through which air will be introduced tothe ame behind the bridge-wall from the chamber below said floor. Insuch case there must be sufficient openings in the sides of the easementto admit air under said perforated ioor; and these openings may beprovided with regulating-Valves, to control the admission of air.

The perforations in the steam pipe f discharge through small nipples i,which coincide with the somewhat larger perforations in the inner wallofthe chamber E, as shown on enlarged scale in Fig. 3.

I do not introduce steam into the fire-box under the supposition thatthe steam actually burns; but I employ the steam-pipe f simply as ablower, for forcing air into the fire-box, and disseminating and mixingit with the gaseous products of combustion arising from the burningfuel.

I deem it essential that the air introduced back of the bridge-wall beintroduced below the top of said wall, in the lower part of the flamebed, at a point near said bridge, and also at one or more points betweenthe point last mentioned and the rear end of the boiler.

I am aware that an attempt was long ago made to improve a furnace byintroducing superheated steam mixed with hot air into the fire-box, andhot air unmixed with steam into the flame-flue, just back of thebridge-wall, immediately under the boiler, and above the Haine-bed,through perforated pipes, and that va patent was granted to one C.Buckhardt,

June 5, 1849, on a furnace constructed to effect said object. I do nottherefore claim, broadly, introducing air and steam into the fire-box,and pure air into the flame-bed or iue back of the bridge-wall throughperforated pipes; but

A perforated air-due above the furnacegrate inclosing a perforated steampipe, provided with nipples, as described, for blowing air and steaminto the ireboX, in combination with perforated air-fines below the topof the bridgewall, and between it and the rear end of the boiler, forintroducing pure air to the lower portion of the flame-bed, all beingconstructed, combined, and arranged to operate substantially asdescribed.

G. W. CUMMINGS.

' Witnesses J. J. CooMBs, J. L. GooMBs.

